Granulomatous mastitis, erythema nodosum and arthritis syndrome: case-based review.

Granulomatous mastitis (GM) is a rare form of inflammatory breast condition associated with unilateral or bilateral breast pain, swelling and mass formation. Although the disease pathogenesis remains unknown, several reports have associated GM with manifestations such as erythema nodosum and occasionally with arthritis, suggesting that GM might have an autoimmune disease component. We aim to describe two cases of coexistence of GM, erythema nodosum, and arthritis. We also conducted a literature review to comprehensively assess and describe the characteristics of patients with GM, erythema nodosum, and arthritis, and identify effective treatment options. A literature review was conducted using PubMed and EMBASE, and 14 case reports/series were retrieved, with a total number of 29 patients. All patients are women and unilateral breast involvement was evident in the majority of patients. Nine patients (31%) presented with arthritis, 6 patients (20.7%) had a fever, and 6 patients (20.7%) developed the symptoms during pregnancy. All patients had normal chest radiograph and tissue cultures were negative. In most of the cases (n = 25, 86.2%), symptom improvement was observed with glucocorticoids and four patients (13.8%) underwent surgical treatment for the GM. Given the clinical characteristics of patients with GM, with erythema nodosum, with or without arthritis, and the positive response to glucocorticoids, we propose that the described phenotype represents an underrecognized systemic autoimmune disease that could be designated by the acronym "GMENA" (granulomatous mastitis, erythema nodosum, arthritis) syndrome. Further studies are needed to elucidate the pathogenesis of the syndrome.